The "pause" in global warming comes from bad data

Global temperatures haven't gone up in the last few years. Does that mean climate change isn't happening? No. In this video, York University chemist Kevin Cowtan explains very carefully how he and his colleague discovered that the "pause" is a fiction, the result of bad data and bad statistical reasoning.


Climate change deniers have jumped on a batch of incomplete, poorly-analyzed climate data which suggests the planet's warming trend is "on pause." If there's a pause, they argue, perhaps predictions of climate change are wrong. Unfortunately for the future of our planet, the pause only exists if you ignore a lot of temperature data.

Illustration for article titled The "pause" in global warming comes from bad data

Cowtan and geography researcher Robert Way have just published their new study in the Quarterly Journal of the Royal Meteorological Society. In a nutshell, the main problem is that deniers are using surface temperature data from the UK Met Office, the region's weather service. But the Met Office has no data for key areas, including the Arctic and parts of Africa. To determine global temperature rise — and the "pause" — the Met Office produced a global average by simply leaving out data on these regions. This is a very unreliable way to create a model of global temperature. What Cowan and his colleagues did instead was to supplement the Met Office surface data with satellite data on the Arctic and parts of Africa.

They ran several tests to determine whether their method could produce reliable temperatures for regions where they still had no data, and their method did a much better job than the Met Office. The way they tested their method was simple. They removed data actually covered by the Met model, and then ran simulations to see whether they could accurately predict those "missing" temperatures. They found that their model predicted temperatures about twice as well as the Met Office model. So they're confident that their assessment of global temperature rise is far more accurate than the one generated with Met Office data and statistical modeling.

TL;DR: When you account for the rapid temperature rise in the Arctic, instead of leaving it out, you'll see that there is almost no pause at all.

There are two other facts to keep in mind. One is that rising temperatures in the ocean are in the deep ocean, not on the surface. So a surface temperature measure does not reflect actual warming in the oceans. And two, climate is a chaotic system. We will see jumps and dips and pauses all the time, on the scale of a few years. But when you look at the trends decade by decade, you can still see an obvious trend upward in global temperatures.


Read more about this study in The Guardian, or read the scientific paper in Quarterly Journal of the Royal Meteorological Society.



Wait a minute, how could climate change deniers believe that global warming is on "pause", if they don't even believe it's happening to begin with?